Safety-fuse indicator.



PATENTED DEC. 17, 1907.

G: N. SAGHS;

SAFETY 'IXNDWATGBQ APPLIGATIGH EIXXEH EAR-11.1804.

250 V0 LTS AMPS.

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Y Vit messes CAROLINE N. SACHS, OF HARTFORD, CONNECTICUT.

. SAFETY-FUSE INDICATOR.

Specification of Letters Patent.

Patented Dec. 17, 1907.

Application filed March 11. 1904. Serial No. 197.652.

To cll whom it may concern:

Be it known that I, CAROLINE N. SAcI-rs, a citizen of the United States, and residentof Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Safety-Fuse Indicators, of which the following is a full, clear, and exact specification. v

This invention relates to improvements in indicating devices for safety fuses which are inclosed in tubes and casings, and known in the art as inclosed fuses, the object of the invention being to providemeans for automatically indicating the condition of the electrical conductor or fuse stri whether it is intact, or burned out, and to provide improved means for automatically changing the indicationu on the burning out of the fuse. As such "uses are entirely concealed from view it has been the practice to combine Withthe main conductor inclosed in the casing, and surrounded bythe ma terial contained therein a fine shunt wire, connected in multiple with the main fuse stri and placed either entirely upon the su ace of the casing, or partly upon the inside of the casing, but with a portion thereof brought to the surface of the casing. In either case, it is intended that when the' main fuse strip is ruptured by an excess of current the fine wire will also be ru tured as it is then the only remaining pati for-the current, and as this fine wire is visible upon the surface of the tube, or affects by ignition a visible device, it shows the condition of the interior fuse in this way. The objection to this form of indicator, however, is due to the fact that very frequently this shunt wire is improperly connected, so that it does not receive the current after the rupture of the main fuse, and therefore no indication is obtained. Such indicators also give forth more or less s arking'or flashing, which it is desirable to e iin'inate.

In order to eliminate the difficulty I provide an indicator controlledby an electrically inert but disruptible retainer composed. of a fine wire, or silk or linen cord, or strip, which may be eitherof insulating or corn ducting material, and I pass this wire strip or cord, either longitudinally or transversely through the tube, so that some portion thereof is brought in conta .t with, or in close proximity to, the fuse strip, This cord is connected at either one or both of its ends the exterior of the tube or casing, or so that it may be seen or felt. from the outside, but so arranged that, so long as the string, cord,

or wire is intact, due to the continuous condition of the fuse-strip, the spring or other device is held inert; but as soon as the strip has fused, the consequent heating and slight tendency to are causes a burning and severing of the retainer strip, or cord, which results in a releasing of the spring or other device, and thus gives an indication externally that the fuse strip has been ruptured. Figure 1 -is a plan View of this improved fuse. Fig. 2 is a side view in section through the longitudinal center of the fuse showing the fuse intact. Fig. 3 is a transverse sectional view on the line of Fig. 2, sho wing the changed position of the indicating means after the fuse strip has been burned out. Figs. 4 and 5 are-transverse sectional views showing a modified form of the indicatingv means. Fig. 6 is a sectional side view of a fuse with another modified form of the indicating means. Fig. 7' is an enlarged view of the indicating means and socket of F ig. 6 after the fusible strip or conductor has been burned out.

The general fornrof fuse here shown is that of a well-known type which adapted.

to be placed in a suitable clip or holder to which the circuit wires are attached, and having means for connecting the wires with the terminals of thcfuse strip.

The fuse shown in Figs. 1, 2 and 3 consists of an outer casing 11 containing a filling it) of any suitable insulating material heldin place by ferrules 12 and 13 on the ends of the casing 11.. These ferrules form the-external contacts of the fuse. The filling H) incloses a fusible conductor or fuse strip,ns it is commonly termed 1.5 which is soldered to terminals 16 which connect it with liu ferrules l2 and. 1.3. ()n the outside of the casing is a spiral indicator formed of spring wire or some other suitable material, one end of which is held in place under the label 21, while the other end is secured to :1 retainer 24 of thread or fusible wire which passes down through the casing 11 and flu filling 19 to the opposite side of the casing I I where it is secured by any suitable mean as for instance the tack 25. The retainer 3 l is in contact wither close to the fusible st rip 15, so that when the strip is burned ulll rho retainer 21 is also burned in two, thus reto a small spring of suitable form, either on l leasing the inner end of the spiral indicator ill?) ill) .-5 the indicator consists of a flat spring or 23, and permitting it to rise to the position shown in Fig. 3.

In the modified form-shown in Figs; 4 and strip of wire 30, the central portion of which is held in place under-the label 29 while its two ends are retained closely against the casing 11 of the fuse by the retaining thread or wire 31. The latter joins the two ends of the indicator 30, being in contact with or tainsa helical spring 36 the outer end of which is secured to one. end of the retainer 38, which keeps it compressed within the socket. The retainer 38 passes across or in sufficiently close proximity to the fusible strip to be disrupted by the direct heat from the burning out of the fuse. The other end of the retainer is secured in any convenient way, being here shown as being fastened between the casing 11 and the ferrule 13.

The direct heat of the burning out of the fusible strip 3.4 severs the retainer 38, thus releasing the outer end of the helical spring 36, and permitting it to project upwardly from the socket.

W'hichever form of indicator is employed, its whereabouts upon the external surface of the fuse may be ermanently indicated by means of the label or otherwise. As shown in Fig. 1, the label is provided with an opening through which the indicator may be seen; and its condition instantly observed at all times. In many ways whichwill suggest themselves to those familiar with this art, the embodiments of this invention herein shovm and described may be modified to suit the various conditions of service.

The retainer may be of any suitable material, and may be either a conductor or a non-conductor of electricity; and if .a conductor it may carry a portion of the current but is preferably arranged to be electrically inert in the sense that it conducts no portion of the current directly from one external contact to the other external contact. In any case, however, the retainer, or some portion thereof, should be disruptible upon rupture of the fuse strip 15, and preferably by the direct heat of that rupture, m which latter case the retainer or some portion'thereof should be placed in suitable proximity to that portion of the fusible strip, preferably the center of its length, which will be first ruptured by an excess of current, so thatthe. heat generated by the rupture of th fus ble strip shall directly disrupt the retainer.

The term electrically inert as between the external contacts of the fuse is heieinemployed to distinguish this invention from those in which the indicator normally forms a part of the main'fuse, or forms a shunt circuit around the entire mam fuse, and in which such indicators are ruptured by current carried directly from one external con-.

tact to the other external contact.

I claim as my invention:-

1. The combination in an inclosed fuse, of conductor fusible by the current, amembcr inclosed within the fuse structure and electrically inert as between the external contacts of the fuse, but disruptible upon the rupture of the fusible conductor, and

movable means in connection with the said member for indicating whether or not it is disrupted.

a conductor fusible by the current, an external indicator, a retainer inclosed Within the fuse structure and electrically inert as between the external contacts, but directly disruptible by the heat of rupture of the conductor for holding the indicator in its'position indicative of the normal condition of the fuse.

i 3. The combination in an inclosed fuse, of a conductor fusible by the current, an external indicator therefor, and a retainer inclosed within the fuse structure and electrically'inert as between the external contacts, but arranged within the disrupting influence of the conductor for holding the indicator'in its position indicative of the normal condition of the fuse.

4. The combination in an inclosed fuse, of a fusible conductor, an external indicator and a retainer inclosed within the fuse structure and electrically disconnected from the fuse,

but subjected to disruption by the heat of rupture of the fuse, for holding the indicator in its position indicative of the normal condition of the fuse.

5. The combination in an inclosed fuse, of a fusible conductor, an indicator'electrically disconnected from the fuse, and a retainer inclosed within the fuse structure and disruptiblc by and placed within the burning out influences of the fuse and connected with 2. The combination in an inclosed fuse, of

the indicator for holdingit in the position indicative of the intact condition of the fuse.

6. The combination in an inclosed fuse, of

a fusible conductor, an indicator electrically disconnected from the fuse and indicating by changes in its position whether the fuse is intact or burned out, and a retainer separate from, but disruptible by, and placed within the fuse structure and within the burning out influences of the fuse for holdmg the 1n- ,dicator in the position indicative of the intact condition of the fuse.

"7. The combination in aninclosed fuse, of aiusible. conductorj'an indicator and a resubjected to disruption upon the disruption of the fuse, but electrically inert as between the external contacts of thefuse, for holding the indicator in its positionindicative of the normal condition of the fuse 8. The combination in an inclosed fuse, of a fusible conductor, an indicator and a re-.

' tainer situated within the fuse structure and subjected to disruption upon the disruption vof the fuse, but electrically inert as between the external contacts of the fuse, for holding the indicator in the position indicative 'of'the intact condition of the fuse, a portion of the retainer being located in proximity to the central portion of the fuse. I i

9. The combination, ina safety fuse, of an inclosing casing, a fusible conductor situated within the casing, a resilient indicator, an electrically inert retainer Situated within the casing, separate from the fuse, but directly disruptible by the burning out of the fuse and connected with the indicator to hold it out of its normal position of repose.

10. A mechanical indicator for safety fuses, comprising an inclosing casing, a resilient indicator, an electrically inert refuse strip.

tainer within the casing, but separate from the fuse strip thereof, for holding the indicator in'coinpression, and passing inproximity to the fuse strip, the retainer being directly disruptible by the burning-out of the- 11. A mechanical indicator for inclosed fuses comprising a resilient indicator, a retainer, disruptible by the burning out'of the fuse strip, for holding the indicator against its resilient tendency, and a label for attaching the indicator to thecasingof the fuse structure.

12. A mechanical indicator for inclosed fuses comprising a resilient indicator, a retainer, disruptible by the burning out of the fuse strip, for holding the indicator against its resilient tendency, and a label for showing the location of the indicator, and for securing it in that position.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

- CAROLINE N, SACHS.

Witnesses: Y

CAROLINE M. BREOKLE, WM. H. HoN'Iss. 

